Technical Abstract:
Known applications of several past-use organochlorine pesticides were made to small cinder-block-confined plots in the early 50's at the USDA Beltsville Agricultural Research Facility. These plots have remained relatively undisturbed for more than 45 years. Technical BHC, DDT and chlordane treated plots were sampled by taking cores that were divided into two layers. Each layer was extracted and analyzed by chiral column gas chromatography. The relative amounts of the chiral separated components for each of identified enatiomeres in these samples were compared to their relative amounts in fresh standards. Quantitative data were also obtained in order to consider the disappearance of these chemicals over this time period and to compare these to the initial loss curves that were determined by other investigators. The significance of the chemical changes are discussed relative to the chiral selectivity of the microbial degradation processes.